2001/10/30 by Simon Ellis, S. C. Ellis, L. R. Jones · 1 citation
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Galaxy groups and clusters #Luminosity #Luminosity function #Optics #Physics #Redshift #X-ray #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.2002.05092.x
published as Mon.Not.Roy.Astron.Soc. 330 (2002) 631 · 12 pages, 7 figures. Accepted for publication in MNRAS
arxiv created 2001/10/30 · openalex publication_date 2002/03/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The X-ray luminosities of the <it>Einstein</it> Extended Medium Sensitivity Survey (EMSS) clusters of galaxies with redshifts 0.3<<it>z</it><0.6 are remeasured using <it>ROSAT</it> Position Sensitive Proportional Counter (PSPC) data. It is found that the new luminosities are on average 1.18±0.08 times higher than previously measured, but also that this ratio depends strongly on the X-ray core radii we measure. For the clusters with small core radii, in general we confirm the EMSS luminosities, but for clusters with core radii >250 kpc (the constant value assumed in the EMSS), the new luminosities are 2.2±0.15 times the previous measurements. The X-ray luminosity function (XLF) at 0.3<<it>z</it><0.6 is recalculated and is found to be consistent with the local XLF. The constraints on the updated properties of the 0.3<<it>z</it><0.6 EMSS sample, including a comparison with the number of clusters predicted from local XLFs, indicate that the space density of luminous, massive clusters either has not evolved or has increased by a small factor ∼2 since <it>z</it>=0.4. The implications of this result are discussed in terms of constraints on the cosmological parameter Ω<inf>0</inf>.